1. Field of the Invention
The present invention relates to a gearbox apparatus.
More specifically, the present invention relates to a gearbox apparatus having at least three gearwheels disposed within a housing and in which one of the gearwheels is selectively replaced by a different gearwheel for generating a different gear ratio.
2. Background Information
Gearboxes enable the generation of a gear ratio between an input drive of the gearbox apparatus and a driven output thereof.
In the prior art, in a simple three gearwheel arrangement, the input drive is secured to the first gearwheel and the driven output is secured to the third gearwheel with the second gearwheel intermeshing with both the first and the third gearwheel. Such an arrangement generates a specific gear ratio between the input drive and the driven output.
However, it is often necessary to change a specific gear ratio and this change typically will require the replacement of the entire gearbox apparatus with a replacement gearbox having a first gearwheel that is larger or smaller in diameter than the original first gearwheel. The replacement gearbox consequently has a first gearwheel having a different number of gear teeth for generating a different gear ratio.
Consequently, the replacement gearbox must have a different size gearbox housing in order to accommodate the different diameter first gearwheel.
The provision of numerous size gearbox housings obviously increases the cost of production of such gearboxes.
Additionally, because the size of the first gearwheel has been changed and consequently the size of the gearbox housing has changed, it follows that the distance between the input drive and the driven output will change when the replacement gearbox is fitted thus adding to the expense of installing a replacement gearbox.
The present invention provides a unique gearbox apparatus which overcomes at least both of the aforementioned problems by the provision of a one size gearbox housing in which the housing defines a first enclosure for the selective reception therein of at least two different diameter size first gearwheels. Such an arrangement is made possible by having the axis of rotation of the second gearwheel disposed at selected locations with each location being the same radial distance from the axis of rotation of the third gearwheel. The selected locations permit intermeshing of the second gearwheel with both the first and the third gearwheel and the replacement first and the third gearwheel.
Therefore, it is a primary feature of the present invention to provide a gearbox apparatus that overcomes the problems associated with the prior art arrangements.
Another feature of the present invention is the provision of gearbox apparatus that greatly reduces the cost of the provision a several gearboxes having different gear ratios.
Another feature of the present invention is the provision of a gearbox apparatus that provides a replacement gearbox having a different gear ratio while maintaining the same distance between the drive input and the driven output.
Other features and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description of a preferred embodiment of the present invention contained herein.